1. Field of the Invention
The present invention relates to a database processing method.
2. Prior Art
As a data storage method of table of relational database management system, there is a partitioning of table. As a method of table partitioning storage, there are known methods such as the key range partitioning, and hash partitioning. A technique applying these techniques is disclosed in the JP-A No. H6-139119 and JP-A No. H6-314299. In addition, a partitioning method that combines a plurality of steps of these methods is disclosed in the JP-A No. H10-269225.
The reason for partitioning these tables is not simply because a large amount of data may not be stored in one external storage device. The improvement of processing speed and concurrency by referring and updating only the specific external storage device or a logical database storage area at the time of searching is the aim, also the merits in the operation side by allowing localizing the backup and reconstruction is another aim.
In the key range partitioning and the hash partitioning, there are cases in which values of one column of table are used and cases in which values of a plurality of columns of table are used. When values of a plurality of columns of table are used, values of a plurality of columns are concatenated to insistently determine a logical database storage area as one key. In addition, in the partitioning method that combines a plurality of steps of these methods such as that disclosed in the above JP-A No. H10-269225, the multiple components of hardware configuration is used by such as the partitioning of database of first step to each of computers in a group of computers, the partitioning of database of second step to each of processors in each computer, furthermore the partitioning of database of third step to each of external storage device in each of processors. The partitioning in each phase in this is to insistently use one key.
As another conventional example, there is JP-A No. H10-240744. This is a partitioning of database with a range of one key. Furthermore, when defining a table the storage position of data is not itself determinable from the value of key. When storing data, in order to memorize one by one where is stored the data, the number of storage range of records and the key value that is included in the records are corresponded to store in the key information storage area.
Still another conventional example, there is JP-A No. H5-334165. In this disclosure the key that is used for the key range partitioning is only one key of primary key. Then, the partitioned part of table is distributed to the local database processing means to maintain. In such a circumstance the searching by a second key is enabled.
In the partitioning storage techniques of the Prior Art, when one table is partitioned to a plurality of storage areas in one processor, the key that is used for the partitioning condition is only one. Therefore in the condition that is other than the partitioning key that is only one, the narrowing of storage area is not allowed, so that the every data storage area is to be subject to be processed. Also, when a plurality of keys is used in a combination of multiple steps, the system configuration of hardware is dependent.